Someone's math is off...

Picked up the renewal on the pup's viagra and noticed that the slip says it has 20 day's worth of meds. Problem is there are 5 pills, she gets 1/4 pill twice a day - a.k.a. 1/2 a pill a day. In my calculator that's 10 days, not 20.

 

::sigh::

 

Is this lack of skills human error, computer glitch, or a little of both? And does it explain the economic problems we're seeing today?